Nuprl Lemma : member-concat
∀[T:Type]. ∀ll:T List List. ∀x:T.  ((x ∈ concat(ll)) 
⇐⇒ ∃l:T List. ((l ∈ ll) ∧ (x ∈ l)))
Proof
Definitions occuring in Statement : 
l_member: (x ∈ l)
, 
concat: concat(ll)
, 
list: T List
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
and: P ∧ Q
, 
so_apply: x[s]
, 
implies: P 
⇒ Q
, 
concat: concat(ll)
, 
top: Top
, 
iff: P 
⇐⇒ Q
, 
false: False
, 
rev_implies: P 
⇐ Q
, 
exists: ∃x:A. B[x]
, 
or: P ∨ Q
, 
cand: A c∧ B
, 
guard: {T}
Lemmas referenced : 
list_induction, 
list_wf, 
all_wf, 
iff_wf, 
l_member_wf, 
concat_wf, 
exists_wf, 
reduce_nil_lemma, 
false_wf, 
nil_member, 
nil_wf, 
reduce_cons_lemma, 
or_wf, 
equal_wf, 
cons_member, 
cons_wf, 
member_append, 
append_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
sqequalRule, 
lambdaEquality, 
productEquality, 
independent_functionElimination, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
productElimination, 
addLevel, 
allFunctionality, 
impliesFunctionality, 
because_Cache, 
existsFunctionality, 
andLevelFunctionality, 
existsLevelFunctionality, 
rename, 
universeEquality, 
unionElimination, 
dependent_pairFormation, 
inlFormation, 
inrFormation, 
equalitySymmetry, 
hyp_replacement, 
Error :applyLambdaEquality
Latex:
\mforall{}[T:Type].  \mforall{}ll:T  List  List.  \mforall{}x:T.    ((x  \mmember{}  concat(ll))  \mLeftarrow{}{}\mRightarrow{}  \mexists{}l:T  List.  ((l  \mmember{}  ll)  \mwedge{}  (x  \mmember{}  l)))
Date html generated:
2016_10_21-AM-10_33_57
Last ObjectModification:
2016_07_12-AM-05_46_02
Theory : list_1
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